Biomechanics and Physiology of Uphill and Downhill Running
The defining terrain review
Key Findings (abstract)
Uphill (vs level): higher step frequency, more internal mechanical work, shorter swing/aerial phase, greater duty factor; a progressive shift to a mid-/fore-foot strike; lower-limb muscles perform a higher net mechanical work to raise the body's potential energy — power output rises at all joints, particularly the hip, so uphill requires greater muscular activity than level or downhill running
Downhill (vs level): longer aerial time, lower step frequency, lower duty factor; shift to a rear-foot strike; energy dissipation (braking) generally prevails over energy generation
Energy cost of running: increases linearly with positive slope; on descents it decreases until a minimum at −20%, after which it increases again
The authors: slope effects on biomechanics, muscle-contraction patterns and physiological responses have important implications for injury prevention and for success in graded-running competitions
Downhill muscle damage (eccentric loading → soreness) is discussed in the full text; the abstract states only that energy dissipation prevails (full text; not checked against the abstract)
Practical Application
Review of graded running: uphill = higher cadence, more work at every joint (especially the hip), fore-foot shift, energy cost rising linearly with grade; downhill = longer flight, lower cadence, rear-foot strike, braking work, energy cost falling to a minimum at −20% grade and then rising. A masters trail runner needs BOTH abilities trained specifically — they are different tasks
Do not judge downhill load by HR/oxygen — the energy cost is low down to −20%, while the braking (energy-dissipation) demand is what the muscles pay for; accustom progressively (repeated bout effect, REF-549)
Steeper than about −20% the energy cost rises again: very steep descents are neither "free" nor cheap to run hard. Inference from the cost curve
Quadriceps strength and eccentric work protect on descents (REF-513 strength, REF-517 tendons). Not from this paper; the base's own practice
Limitations
Narrative review; specific values depend on gradient/speed/surface, and the abstract gives only the −20% cost minimum
Laboratory (treadmill) data do not fully reflect technical trail (rocks, roots, turns)
How this entry was checked and changed
Why this level
regraded 2026-09-27 from A: narrative review without systematic method (leading graded-running research group)
Content correction 2026-09-27
Key findings rewritten to the abstract's actual biomechanical list (step frequency, duty factor, aerial time, foot strike, joint power, energy-cost minimum at −20%)
"Downhill → muscle damage (DOMS), impact/braking forces, quadriceps/joint load" -> the abstract says energy dissipation prevails; DOMS labelled as full text
Level A -> B+ (narrative review); Sport line "trail-running, running, strength" -> "trail running, running"